Ten Eco-Friendly Companies

In 2001, the unmanned, $15 million Helios Prototype solar electric plane built by NASA set a world record for flight altitude. During a later flight, it crashed into the Pacific Ocean, but the project was still considered an engineering breakthrough, thanks in part to its ultra-lightweight solar panels created by SunPower Corp.

The Silicon Valley company's panels can produce up to 50 percent more power than most others on the market. They're also solid black, a big selling point with homeowners who want them to blend into their roofs. Esthetics alone could give SunPower an advantage in the fast-growing residential solar market. SunPower, a subsidiary of Cypress Semiconductor, hopes to raise $100 million in an upcoming stock offering. (Because of the pending offering, SunPower could not comment.)

The company faces plenty of hurdles. By all accounts, growth in the industry is likely to be slow and steady, and analysts say that profit margins are slim--supplies of polysilicon, a key ingredient in panels, are limited and expensive. SunPower's hope is that more consumers will follow the lead of people like Titus Brenninkmeijer. As the founder of an international alliance to help entrepreneurs in developing countries promote solar power, he's presold on the technology. In July, he spent about $80,000 to outfit his Pasadena, Calif., home with SunPower panels. "They make the most efficient modules," he says, adding that he expects to recoup his investment in 10 to 12 years. He also gets to make his neighbors jealous. In the blistering California summer months, Brenninkmeijer's panels actually generate more power than the family of five uses. "Our neighbors think it's neat because our meter spins backward and we actually make money," he says.

--Jennifer Ordonez

10 A Jolt of Conservation

Comverge, Inc.: Its technology cuts power usage, and saves money, for utility customers.